Saturday, December 29, 2007

Also time goes slower

For a decade, scientists have puzzled over a surprising phenomenon: Supernovae stars viewed at extreme distances seem to be moving away from us faster than those nearby.

Most researchers have assumed that the stars have somehow accelerated – or that, more precisely, the rate of the expansion of the post-Big Bang universe itself has accelerated over time.

This was particularly odd given that the universe was thought to be dominated by matter, which should, through the aggregate gravitational effect of each bit pulling on the others, have led to a deaccelerating expansion, rather than the opposite. Thus, scientists have postulated an unknown kind of energy, now known as "dark energy," which would be responsible for the acceleration.

But hold on just a minute.

A group of scientists from the University of the Basque Country in Bilbao, and Spain's University of Salamanca have offered a different idea. Maybe it's the passage of time itself that's slowing down, they say. The distant galaxies only look like they're accelerating because our deep-space telescopes are essentially looking back in time to see them, to when time was going faster.

The theory, outlined in the New Scientist and the UK Telegraph, and in a paper published in Physical Review D, is based on a complex bit of string theory that remains entirely speculative today. Under this theory, our entire universe is embedded in a multidimensional "brane," which itself is floating through a higher dimensional space that we can't detect.

Naturally, the theory has a few chilling conclusions. If time is slowing, it could – in billions of years – actually come to a complete halt, University of the Basque Country professor José Senovilla told New Scientist.

Would that mean everything freezes in place forever? Apparently. Does forever mean anything if time itself has literally stopped? Pass...

In short, a brain twister. Of course, there's a catch, which Senovilla says his group hasn't yet considered. Another group of physicists has postulated that there may actually be two dimensions of time, rather than just one we all know and fear. Which would explain where all that lost time goes, I suppose.